In recent years, with the development of smartphones and tablet computers, capacitive touch screens have been rapidly developed in markets. When a finger or other object touches the screen, a coupling capacitance is formed between the finger and an electrode of the touch screen, and the position of the touch point can be obtained by detecting a change in capacitance at the electrode.
FIG. 1A is a cross-sectional diagram showing a display device provided in a related art (Chinese Patent application No. CN200910132037.9). The display device includes at least an array substrate, an opposite substrate disposed opposite to the array substrate, and a liquid crystal layer 30 between the array substrate and the opposite substrate, where, the array substrate is formed of a Thin Film Transistor (TFT) substrate 11, a gate electrode layer 12 and a common electrode layer 13 both on the TFT substrate 11, the opposite substrate is formed of a protective layer 21, a sensing electrode 22, a glass substrate 23 and a color filter 24, and a capacitance C1 is formed between the sensing electrode 22 and the common electrode layer 13, where, the common electrode layer 13 can be directly disposed on the TFT 11 as shown in FIG. 1A, or disposed at a side of the opposite substrate facing to the array substrate (not shown) and it can also be disposed at a side of the opposite substrate that is away from the array substrate (not shown). FIG. 1B is a top view showing the common electrode layer 13 of the display device provided in the related art. The common electrode layer 13 functions as a driving electrode in the display device and is divided equally into a number of rows according to the number of channels of drive signals. As shown in FIG. 1B, the common electrode layer 13 is divided into n driving electrodes, and labeled with 13-1, 13-2, 13-3, . . . , 13-n. These rows are scanned in a line-by-line scanning manner or in a lines-by-lines scanning manner to sequentially scan the driving electrodes 13-1, 13-2, 13-3, and so on. FIG. 1C is a schematic diagram of driving the common electrode layer 13 in the related art, where, the FIG. 1C shows the sensing electrode 22 perpendicular to the driving electrodes. When the electrodes in the common electrode layer 13 are scanned, the capacitance between the sensing electrode 22 and the scanned electrodes are changed. As shown, the electrodes are represented by 13-1, 13-2, 13-3, 13-4, and 13-5, respectively, and the capacitances between the sensing electrode 22 and the scanned electrodes are represented by C1-1, C1-2, C1-3, C1-4 and C1-5, respectively.
In the related art, the common electrode layer is divided into a number of rows according to the number of channels of drive signals to be multiplexed as driving electrodes. When the size of the panel is larger, a load of the drive signal becomes larger, so that the charging time required for the common electrode layer will become longer accordingly. For an In-cell touch screen with a time-sharing operation, a competitive relation exists between the touch electrode operating time and the driving electrode operating time, so that when the load of the driving electrode is larger, the required charging time is longer accordingly, thereby affecting the drive capability of the display device.